Integration and packaging issues are one of the main obstacles for the commercialization of micro devices e.g., radio frequency (RF) microelectromechanical systems (MEMS) microswitches, light-emitting diode (LED) display systems, MEMS or quartz-based oscillators.
Traditional technologies for transferring of devices include transfer by wafer bonding from a transfer wafer to a receiving wafer. One such implementation is “direct printing” involving one bonding step of an array of devices from a transfer wafer to a receiving wafer, followed by removal of the transfer wafer. Another such implementation is “transfer printing” involving two bonding/de-bonding steps. In transfer printing a transfer wafer may pick up an array of devices from a donor wafer, and then bond the array of devices to a receiving wafer, followed by removal of the transfer wafer.
Some printing process variations have been developed where a device can be selectively bonded and de-bonded during the transfer process. In both traditional and variations of the direct printing and transfer printing technologies, the transfer wafer is de-bonded from a device after bonding the device to the receiving wafer. In addition, the entire transfer wafer with the array of devices is involved in the transfer process.
Another existing technique for transferring semiconductor die uses elastomeric stamps. In this technique the surface of the stamp adheres to the surface of the semiconductor die via van der Waals forces.